Reflective Glass Beads

reflective glass beads used in road marking lines

Glass bead is a colorless, transparent pellet, with refraction of light, and light focus, and directional reflection function. The glass beads were mixed with or spreading on the surface of the road marking coating film, to reflect the light back to the car driver's eyes, thus greatly improve the visibility of the markings.

Reflective principle of glass beads in road marking lines

The reflective performance of road lines is formed that car lights will be reflected back to the driver's eye by glass beads in the marking paint. Each glass beads protrusion of the coating surface is a reflective element, when car lights incident on glass beads, the incident light in the glass beads refracted at its inner and is reflected back in the direction of light source, on the reflection coating layer formed by the bottom of the glass beads and paint coatings.

reflective principle of glass beads in road marking lines

Tips for glass beads spraying

In order to form a good reflection conditions, the following points are very important:

1. Coating surface glass beads spreading in moderation. Spreading of hot-melt coating of glass beads is generally about 20%, the best reflective properties, as picture(c) . Excessive glass beads easy to accumulate dusts, affect the reflection effect, as picture(d). When glass beads proportion is too small, the reflected light is too weak, with poor reflective effect.
2. The glass beads spherical rate is required above 70%. If too irregularly shaped glass beads, the directional reflection of light can not be formed, a reflective performance of road marking lines will be affected.
3. The position of glass beads should be appropriate, best to half-embedded, semi-exposed, as picture(c). Glass beads floating in the paint, as picture(a), not only easy to fall off, but will astigmatic light. Glass beads submerged in the coating will reflect no light, as picture(b).
4. Paint pigment should be in moderation proportion. Too little pigment will cause transmittance, decreasing reflectivity.
5. Particle size and refractive index of glass beads have great effect on the lines reflection.

glass beads spraying--reasonable position in the road marking film

Roundness ratio of reflective glass beads

In the road marking industry, reasonable roundness ratio of reflective glass beads is more than 70 percent. But it is not the higher roundness ratio the better. Because, over-high spherical rate of glass beads will make the reflected light too strong, cause strong visual stimulation to the driver. Thus a small amount of irregular glass beads is required, to produce a diffuse reflection, making the reflected light soft.

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